The Effect of Different Rootstocks and Potassium Sulfate Fertilizer on leaf Potassium, Calcium and Sodium in Young ‘Clementine’ Mandarin Trees.

Abstract

This work was undertaken to study the influence of five different citrus rootstocks and the level of potash applications on absorption and accumulation of potassium, calcium and sodium in the leaves of young Clementine mandarin trees. It was also intended to determine whether or not the supply of these three elements was inadequate, satisfactory or unnecessarily high.

Among the rootstocks tested, the Cleopatra mandarin supplied the least but adequate amounts of potassium to the Clementine mandarin leaves. By the end of the fifth growing season in the field, the Troyer citrange rootstock induced the highest postassium and the lowest calcium levels in the scion leaves. Addition of potash in amounts equivalent to half the annual application rate of nitrogen increased significantly the potassium and depressed the calcium contents in the scion leaves, regardless of the rootstock. However, under no potassium fertilization program, potassium as well as calcium concentrations in the Clementine mandarin leaves were always within the optimum nutritional standards if not higher in case of potassium only, depending upon the rootstock used. No effect could be detected between rootstocks or amounts of potassium sulfate fertilizer on the sodium content which was present in amounts less than 0.16%.